One of those three shoggoths have fed recently. You can tell by the shape struggling inside of it as it moves along like Fetishman's shoggoth. Which has two victims inside of it now. Poor Hammond, he didn't deserve it, but he asked for it when he tempted Murphy's wrath. All four shoggoths are now after the group of four. For two of them, the chain links don't matter. They can pass right through them. The other two start climbing.

The group of three at the stepping platforms have probably noticed the tentacle attempting to lash out and grab them. HIT THE DECK! The end is in sight!